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1. 1. Which of the following elements is NOT one of the six that make up 98% of most organisms' body weight? A. hydrogen B. nitrogen C. carbon D. iron ___

2. 2. All atoms of a certain element have the same number of protons. • True False ___

3. 3. All matter is composed of certain basic substances called elements. • True False ___

4. 4. The three isotopes of carbon 12C, 13C and 14C have different numbers of _______? • A. electrons B. protons C. neutrons ___

5. 5. Protons have a __________ electrical charge. • A. positive B. negative C. neutral ___

6. 6. Electrons always have the same amount of potential energy. • True False ___

7. 7. The atomic number of an atom is the same as __________. • A. the atom's mass B. the number of protons the atom has C. the number of neutrons the atom has ___

8. 8. If an atom has an atomic number of 17 and an atomic mass of 35, the number of neutrons in its nucleus equals _____. • A. 17 B. 18 C. 35 D. 52 ___

9. 9. Electrons with the least amount of potential energy are located in the __________ shell. • A. L B. K C. M ___

10. 10. If an atom with an atomic number of 9 and an atomic mass of 19 is electrically neutral, it has __________ electrons. • A. 9 B. 10 C. 19 D. 28 ___

11. 11. Radioactive isotopes are used to __________. • A. determine the age of fossils B. trace chemicals during biochemical reactions C. detect thyroid abnormalities D. all of the above ___

12. 12. Electrons that are farther from the nucleus have more potential energy than electrons closer to the nucleus. • True False ___

13. 13. The subatomic particle with an atomic mass of one and a neutral charge is a(n) __________. • A. proton B. electron C. neutron ___

14. 14. The nucleus contains ________. • A. protons B. electrons C. neutrons D. A and C ___

15. 15. Electron shells, other than the first one, can contain up to eight electrons. • True False ___

16. 16. An electrically neutral atom with an atomic number of 7 will have _____ electron shell(s). • A. one B. two C. three D. four ___

17. 17. Electrically neutral magnesium (atomic number 12) is an example of an inert (non reactive) atom. • True False ___

18. 18. How many carbon atoms are there in a molecule of glucose, C6H12O6? • A. 1 B. 6 C. 12 D. 24 ___

19. 19. If a chemical equation is balanced, there are equal numbers of each specific atom on both sides of the arrow. • True False ___

20. 20. An atom of hydrogen (atomic number = 1; atomic mass = 1) has one proton and no neutrons. • True False ___

21. 21. Which of the following is an inert (non-reactive) atom? • A. hydrogen; atomic number = 1 B. oxygen; atomic number = 8 C. neon; atomic number = 10 D. chlorine; atomic number = 17 ___

22. 22. The sodium ion (Na+) has 12 protons (atomic number of Na = 11). • True False ___

23. 23. Which bond is most easily broken? • A. a hydrogen bond B. a triple covalent bond C. a single covalent bond ___

24. 24. What type of bond is formed when atoms share electrons? • A. ionic B. covalent C. hydrogen ___

25. 25. Chlorine (atomic number = 17) needs _____ electron(s) to fill its outermost electron shell. • A. no B. one C. seven D. eight ___

26. 26. Electrically neutral atoms are called ions. • True False ___

27. 27. In a __________ covalent bond, two atoms share two pairs of electrons. • A. single B. double C. triple ___

28. 28. An equal sharing of electrons creates a __________ bond. • A. polar covalent B. ionic C. hydrogen D. non-polar covalent ___

29. 29. Which of the following is most likely to form an ionic bond with Cl-? • A. F- B. Na+ C. He D. O2 ___

30. 30. Which of the following is an example of a compound? • A. O2B. Na+ C. CO2D. Ne ___

31. 31. What type of bond will form between 2 atoms of nitrogen (atomic number = 7) to form the gas N2? • A. ionic B. triple covalent C. single covalent D. none ___

32. 32. An atom with one electron in its outermost shell tends to be an electron donor. • True False ___

33. 33. A dashed line between atoms represents a(n) _____ bond. • A. hydrogen B. single covalent bond C. ionic D. polar covalent bond ___

34. 34. The chlorine ion (Cl-) has 17 protons and 18 electrons. • True False ___

35. 35. The three dimensional shape of a molecule affects its ability to function. • True False ___

36. 36. Hydrogen bonds form when ___________. • A. atoms share electrons B. a slightly negative atom is attracted to a slightly positive atom C. atoms gain electrons D. atoms lose protons ___

37. 37. Energy is __________. • A. required for a bond to form B. released when a bond is broken C. A and B ___

38. 38. An attraction between oppositely charged atoms forms a _____ bond. • A. polar covalent B. triple covalent C. hydrogen D. ionic ___

39. 39. The atom with greater electronegativity will have a slight positive charge in a polar covalent bond. • True False ___

40. 40. Water is a polar molecule. • True False ___

41. 41. A negative ion _____. • A. has accepted an electron from another atom B. is radioactive and can be used to determine the age of fossils C. will form a polar covalent bond with another atom D. all of the above ___

42. 42. The calcium ion (Ca2+) _____. • A. has accepted two protons B. has given away two electrons C. will form a covalent bond with the chlorine ion (Cl-) D. all of the above ___

43. 43. Water molecules are _____. • A. polar B. hydrogen bonded to one another C. cohesive D. all of the above ___

44. 44. Internal body fluids are kept at a near neutral pH by buffers. • True False ___

45. 45. A pH of 7 is _____. • A. acidic B. basic C. neutral ___

46. 46. Which of the following has a basic pH? • A. lemon juice B. milk of magnesia C. tomatoes D. hydrochloric acid ___

47. 47. Hydrogen bonding ___________. • A. causes water molecules to cling to each other B. allows water to absorb a lot of heat without a huge change in temperature C. must be broken to convert water to steam D. all of the above ___

48. 48. All living things are _____ water. • A. less than 10% B. 10-30% C. 40-60% D. 70-90% ___

49. 49. Which property of water is attributed to its polarity? • A. It resists changes in temperature. B. It has a high surface tension. C. It is the universal solvent. D. It is less dense as a solid than as a liquid. ___

50. 50. Which property of water is responsible for facilitating the flow of water upwards in a tree? • A. It resists changes of state (from liquid to ice or liquid to steam). B. It is cohesive and adhesive. C. It is the universal solvent. D. It is less dense as a solid than as a liquid. ___